About 5% of men are plagued with a distressing condition called Peyronie’s disease — a painful curvature of the penis during erection that can make sex difficult or even impossible.

This week, a drug company promised them some relief: in trials, a drug called Xiaflex reduced the curvature significantly compared with placebo, and also helped men feel less troubled about their condition.

In one trial, average curvature went from 48.8 degrees to 31 degrees in a year, a 37.6 improvement, compared with a change from 49 degrees to 39 degrees in the placebo group, a 21.3% improvement. The treatment is no cure, but “it’s a major advantage over what we have now, which is nothing,” researcher Dr. Culley C. Carson III, a professor of urology at the University of North Carolina, told the New York Times.

If the drug is approved to treat Peyronie’s, it would be marketed to the estimated 65,000 to 120,000 American men who receive the diagnosis each year. Xiaflex’s maker, Auxilium Pharmaceuticals, said that approximately 5,000 to 6,500 of these men are currently treated with injectable therapies or surgery.

Xiaflex was approved in 2010 as treatment for Dupuytren’s contracture, a condition that causes fingers to remain clenched. Xiaflex is an enzyme called collagenase, which breaks down collagen, a key component of the connective tissue found in various organs, including the skin, tendons and cartilage. Both Dupuytren’s and Peyronie’s are caused by an excess of collagen that builds up in the hand or penis.

In Peyronie’s, the collagen contributes to plaques that cause the bent shape. Treatment could involve up to eight injections of Xiaflex into the plaque over a period of months; doctors would also help break up the plaque by hand. Side effects may include pain, swelling and clotted blood within the tissue. Auxilium hopes the treatment will be preferable to surgery — which can cause erectile dysfunction — for many men and doctors.

“Obtaining a statistically significant reduction in penile curvature deformity and improvement in Peyronie’s disease bother without the risks of surgical intervention represents an enormous advantage for eligible patients suffering from Peyronie’s disease,” Dr. Larry Lipshultz, professor of urology and chief of the division of male reproductive medicine and surgery at Baylor College of Medicine, said in a Auxilium statement.